They include discussions of conflict in Vietnam, Soviet relations and the race to space, plans for the 1964 Democratic Convention, and re-election strategy. There also are moments with his children.

The tapes are the last of more than 260 hours of recordings of meetings and conversations Kennedy privately made before his assassination in Dallas on Nov. 22, 1963.

David Coleman, the professor who leads the Presidential Recordings Program at the University of Virginia, on Tuesday called the final recordings significant because while JFK didn't tape himself regularly, he chose to preserve important moments.

The university's Miller Center of Public Affairs already has published three volumes of Kennedy transcripts and is working on another two volumes from recordings that previously went public, Coleman said.

"Kennedy did not tape as systematically as Johnson or Nixon. But what he did tape was often very important discussions," he said.

"What you have is an unusually rich collection of decisions being made in real time."

The recordings also are valuable because they're a raw look inside the Kennedy White House, Coleman said.

"It's all unfiltered," he said. "It hasn't been massaged by committees or by the White House press machine."

Historians may gravitate most to Kennedy's recordings about Vietnam to see where his policy was heading when his presidency ended, Coleman said.

Kennedy kept the recordings a secret from his top aides. He made the last one two days before his death.

Kennedy library archivist Maura Porter said Monday that JFK may have been saving them for a memoir or possibly started them because he was bothered when the military later gave a different overview of a discussion with him about the Bay of Pigs.

The latest batch of recordings captured meetings from the last three months of Kennedy's administration. In a conversation with political advisers about young voters, Kennedy asks, "What is it we have to sell them?"

"We hope we have to sell them prosperity, but for the average guy the prosperity is nil," he says. "He's not unprosperous, but he's not very prosperous. ... And the people who really are well off hate our guts."

Kennedy talks about a disconnect between the political machine and voters.

"We've got so mechanical an operation here in Washington that it doesn't have much identity where these people are concerned," he says.

On another recording, Kennedy questions conflicting reports military and diplomatic advisers bring back from Vietnam, asking the two men: "You both went to the same country?"

He also talks about trying to create films for the 1964 Democratic Convention in color instead of black and white.

"The color is so damn good," he says. "If you do it right."

Porter said the public first heard about the existence of the Kennedy recordings during the Watergate hearings.

In 1983, JFK Library and Museum officials started reviewing tapes without classified materials and releasing recordings to the public. Porter said officials were able to go through all the recordings by 1993, working with government agencies when it came to national security issues and what they could make public.

In all, she said, the JFK Library and Museum has put out about 40 recordings. She said officials excised about 5 to 10 minutes of this last group of recordings due to family discussions and about 30 minutes because of national security concerns.

Porter has supervised the declassification of these White House tapes since 2001, and she said people will have a much better sense of the kind of leader JFK was after hearing them. While some go along with meeting minutes that also are public, she said, listening to JFK's voice makes his personality come alive.

She said he comes across as an intelligent man who had a knack for public relations and was very interested in his public image. But she said the tapes also reveal times when the president became bored or annoyed and moments when he used swear words.

The sound of the president's children, Caroline and John Jr., playing outside the Oval Office is part of a recording on which he introduces them to Soviet Foreign Minister Andrei Gromyko.

"Hello, hello," Gromyko says as the children come in, telling their father, "They are very popular in our country."

JFK tells the children, mentioning a dog Soviet Premier Nikita Khrushchev gifted the family: "His chief is the one who sent you Pushinka. You know that? You have the puppies."

JFK Library spokeswoman Rachel Flor said the daughter of the late president has heard many of the recordings, but she wasn't sure if she had heard this batch.

"He'd go from being a president to being a father," Porter said of the recordings. "... And that was really cute."